Battery

AAAA

1.5V alkaline cell

LR8D425 is a pack label for AAAA — same battery, different name on the package.

Common uses: Styluses · Surface Pen (replaceable gens) · Some remotes

AAAA Diagram

Brand-neutral outline — confirm the tray in your device.

Genuine aliases and pack labels for this battery — not substitutes of a different chemistry.

Same battery / other names

AAAALR8D425

Also sold as

Brand or pack name for the same battery.

From manufacturer-backed notes on devices that use AAAA — not generic advice.

Surface Slim Pen and Slim Pen 2 do not have replaceable batteries — they are rechargeable. Do not buy AAAA for Slim Pen.

Optional tools that fit this cell type — only where the chemistry allows. Separate from the battery answer.

Amazon links may earn us a commission. They do not change the battery answer.

Ansmann Energy Check LCD
Quick household cell check (good / low / replace)
Docs Buy on Amazon More tools
Panasonic eneloop BQ-CC55 charger
Everyday NiMH AA/AAA charging (eneloop ecosystem)
Docs Buy on Amazon More tools
PowerEx MH-C9000 WizardOne Charger-Analyzer
Charge, discharge and measure capacity of NiMH AA/AAA
Docs Buy on Amazon More tools

Battery tester
Quick good / low / dead check for household cells
Crude check only — does not measure capacity under realistic load.
How to test a battery Buy on Amazon

Buy links are optional and separate from the battery answer.

Search Amazon for packs of this battery code.

Buy links go to Amazon (Associates where tagged) or other affiliate programmes when available. They never change the battery answer.

Microsoft Surface Pen replaceable generations: 1× AAAA (OEM). Surface Slim Pen / Slim Pen 2 are rechargeable — not AAAA. AAAA ≠ size 319.